`jestPlaywrightSkip` is not a function (with `xdescribe`)

[yj-ang]

Describe the bug
Using jestPlaywrightSkip (and any other extend methods) with either xdescribe or xit is throwing JS error, which make a test/test suite fail.

To Reproduce
Steps to reproduce the behavior:

1. Use jestPlaywrightSkip with either xdescribe or xit.

Expected behavior
Instead of failing the test/test suite, it should properly skip them.

Screenshots

Desktop:

• OS: macOS
• Playwright version: 1.10.0
• jest-playwright version: 1.5.1